1. Field of the Invention
The present invention relates to an arrangement for sliding and shrinking a hood of shrinking foil over and onto a stack formed by a number of packaging objects. The arrangement includes a vertically movable frame with shrinking devices provided in the upper region of the frame and gripping elements for grasping and pulling down the lower edge of shrinking foil.
2. Description of the Prior Art
Arrangements of the afore-described type are known, e.g., WO No. 82/03833. Compared to arrangements including a device for sliding a hood of shrinking material over a stack and a subsequent shrinking apparatus, they have the advantage that their operation is faster because no transfer times from the hood sliding device to the shrinking device are required. In addition, it is possible to save the times usually required for retracting the gripping elements used for sliding the hood over the stack in the separate hood sliding device and, if a shrinking frame which can be raised and lowered is used, for returning this frame after the shrinking procedure has been concluded. This is because in a combined arrangement of the aforementioned type, the shrinking foil hood can be slid over the stack when the vertically movable frame is lowered and the shrinking procedure can be performed when the frame is again raised or retracted.
In accordance with other known arrangements, e.g., EP No. 0 077 508, the hood of shrinking foil can especially well shrunk onto the underside of the stack. In these arrangements, the stack is raised during the sliding of the hood over the stack and then placed down again after the lower edge of the hood has been turned in and shrunk on. As a result, the lower edge of the hood of the shrinking foil which has been turned in and shrunk on remains fixed during the further shrinking of the side surfaces of the hood. In other words, when the foil becomes shorter during the shrinking procedure of the side surfaces, the bottom edge of the hood cannot be pulled away again from the bottom side of the stack.
It is, therefore, the primary object of the present invention to provide an arrangement of the afore-described type in which the two above-described known devices are combined in a single arrangement in such a way that the structural height of the combined arrangement does not increase.